• Journal of Ginseng Research
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• 제23권2호
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• pp.105-114
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• 1999

본 실험은 백서의 간세포막에서 transferrin receptor(TfR)의 발현에 미치는 인삼 및 3'-methyl-4-dimethylaminobenzene(3'-Me-DAB)의 영향을 연구하기 위하여, 인삼, 3'-Me-DAB 또는 3'-Me-DAB처치후 인삼을 투여한 백서를 부분 간절제한 후 간조직에서 $[^{3}H]thymidine$및 transferrin수용체의 유전자 발현 실험, 그리고 간세포막에서$[^{3}H]thymidine$ 결합 실험을 시행하여 다음과 같은 결과를 얻었다. 1. 8주간 3'-Me-DAB를 투여한 백서에서 간조직의 조직학적 소견은 림프구의 침윤, 담관세포의 증식,교량성괴사 및 이상세포의 증식 소견을 보였다. 그러나 정상 또는 3'-Me-DAB를 투여한 백서에 인삼을 투여하였을 때 간조직의 조직학적 소견은 각각의 대조군에 비해 크게 변화되지 않았다. 2. 인삼 또는 3'-Me-DAB를 투여한 백서에서의 $[^{3}H]thymidine$ uptake는 대조군에서와 비슷하였으나, 부분간절제 수술 후 1일째 간에서는 수술 전보다 현저하게 증가되었다. 특히 3'-Me-DAB투여군의 간조직에서 더 증가되었으며, 이는 인삼 투여에 의해 억제되는 경향을 보였다. 3. 간세포막에서의 transferrin 결합량(Bmax) 및 Kd는 정상 백서에서 각각 6.87pmole/mg protein 및 10.64nM이었으며, 인삼 투여에 의해 크게 변동되지 않았다 그러나 3'-Me-DAB를 투여한 백서에서는 Bmax 및 Kd가 증가되었고, 이 증가는 인삼투여에 의해 감소되었다. 부분 간절제 수술 후 간세포막에서의 Bmax 및 Kd는 모든 그룹에서 수술 후 3일째에는 증가, 수술 후 5일째에는 감소되는 양상을 나타냈다. 그러나 3'-Me-DAB투여 후 간절제 수술군에서의 증가가 가장 컸으며, 이 증가효과는 인삼 투여에 의하여 억제되었다. 4. 부문 간절제 수술 후 간조직에서의 TfR mRrfA 발현은 수술 후 24시간에 최대로 증가되었으며, 이는 3'-Me-DAB를 투여한 백서에서 더 현저하였다. 그리고 인삼은 3'-Me-DAB투여 후 간절제 수술군에서 증가된 발현양을 약간 감소시켰다. 이상의 결과로 백서에서 부분 간절제 수술 및 발암 물질에 의해 간세포막 transffirin수용체는 친화력이 저하된 TfR이 증가될 수 있으며, 이는 일부 이 수용체의유전자 수준에서 조절될 수 있는 것으로 생각된다. 그리고 인삼은 발암물질 투여등으로 간세포의 증식이 촉진되었을 때, 간세포내 핵산 합성 및 TfR mRNA 발현 조절을 통하여 세포막의 TfR출현 및 세포증식을 억제시킬 수 있을 것으로 추측된다.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.2997-3002
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• 2011

A series of hybrid molecules between (R)-lipoic acid (ALA) and the acetylated or methylated polyphenol compounds were synthesized and their in vitro cholinesterase [acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)] inhibition activities were checked. The $IC_{50}$ values of all hybrid molecules for a BuChE inhibition were lower than those of the single parent compounds. Specifically, ALA-acetyl protected caffeic acid (11, ALA-AcCA) was shown as an effective inhibitor of BuChE ($IC_{50}=0.5{\pm}0.2\;{\mu}M$) and also had a great selectivity for BuChE over AChE (more than 800 fold). Inhibition kinetic study indicated that 11 is a mixed inhibition type. Its binding affinity ($K_i$) value to BuChE is $1.52{\pm}0.18\;{\mu}M$.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8155-8159
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• 2014

Background: Breast cancer is the serious health concern in India causing the highest mortality rate in females, which occurs due to uncontrolled cell division and can be metastasize to other parts of the human body. Interactions with estrogen receptor (ER) alpha are mainly responsible for the malignant tumors with regulation of the transcription of various genes as a transcription factor. Most of the drugs currently used for the breast cancer treatment produce various side effects and hence we focused on natural compounds which do not exhibit any toxic effect against normal human cells. Materials and Methods: Structure of human ER was retrieved from the Protein Data Bank and the structures of flavonoid compounds have been collected from PubChem database. Molecular docking and drug likeness studies were performed for those natural compounds to evaluate and analyze the anti-breast cancer activity. Results: Finally two compounds satisfying the Lipinski's rule of five were reported. The two compounds also exhibited highest binding affinity with human ER greater than 10.5 Kcal/mol. Conclusions: The results of this study can be implemented in the drug designing pipeline.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.197-203
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• 2001

A fusion protein, consisting of human epidermal growth factor as a recognition domain and human angiogenin as a toxin domain, can be used as a targeted therapeutic against breast cancer cells among others. The fusion protein was expressed as inclusion body in recombinant E. coli, and when the conventional, solution-phase refolding process was used the refolding yield was very low due to severe aggregation, probably due to the opposite surface charge due to vastly different pI values of each domain. Solid-phase refolding process exploiting ionic interactions between the solid matrix and the protein was tried, but the ionic binding yield was very low regardless of the resins and pH conditions used. To provide higher affinity toward the solid matrix, six lysine residues were tagged to the N -terminus of the hEGF domain When the cation exchange resins such as heparin- or CM-Sepharose were used as the matrix, the adsorption capacity increased 2.5-3 times and the subsequent refolding yield increased nearly IS times compared to the conventional process.

• KSBB Journal
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• 제7권4호
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• pp.302-307
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• 1992

protein phosphatase 2A는 bovine brain homogenate의 세포질 fraction에서 얻어졌다. 기질로서 인산화된 histione H1을 이용하여 측정한 phosphatase 의 활성은 dipalmitoyIphophatidylcholine(DPPC) 혹은 phosphatidylserine/DPPC의 혼합물로 구성된 liposome의 존재하에서 저해되었다. Protein phosphatase 2A의 lipid membrane에의 결합은 다중층 지질막의 혼합물 계에서 liposome 의 양이 증가함에 따라서 상등액 중의 phosphatase의 활성이 감소하는 것으로 확인할 수 있었다. 또한 [$^{125}I$]protein phosphatase 2A가 liposome과 동시에 용출되는 것으로도 확인되었다. 그러나 liposome에 대한 protein phosphatase의 친화력은 높지 않았다. 한편, okadaic acid와 liposome은 협동으로 phosphatase의 활성을 감소시켰다. 이것은 okadaic acid가 lipid membrane이나 membrane에 결함한 phosphatase에는 결합하지 않는다는 것을 의미한다. 그러므로 lipid membrane에 의한 protein phosphatase 2A의 활성 저해 효과는 phosphatase 2A와 lipid membrane과의 결합에 의한 것이라고 설명될 수있다.

• BMB Reports
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• 제30권3호
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• pp.205-210
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• 1997

p53 tumor suppressor plays an important role in the regulation of cellular proliferation. To identify proteins regulating the expression of p53 in rat liver, we analyzed p53 promoter by electrophoretic mobility shift assay (EMSA) and DNase I footprinting assay. We found that a protein binds the sequence CACGTG, bHLH consensus sequence in rat p53 promoter. Southwestern blotting analysis with oligonucleotides containing this sequence shows that the molecular weight of the protein is 100 kDa. This size is not compatible with the bHLH family such as USF or c-Myc/Max which is known to regulate the expression of the human and mouse p53 gene. Therefore this 100 kDa protein may be a new protein regulating basal transcription of rat p53. We purified this 100 kDa protein through sequence-specific DNA affinity chromatogaphy.

• BMB Reports
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• 제42권12호
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• pp.817-822
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• 2009

Type-1 phosphatase (PP-1) was assessed in foot muscle (FM) and hepatopancreas (HP) of estivating (EST) Otala lactea. Snail PP-1 displayed several conserved traits, including sensitivity to inhibitors, substrate affinity, and reduction in size to a 39 kDa catalytic subunit (PP-1c). During EST, PP-1 activity in FM and HP crude extracts was reduced, though kinetics and protein levels of purified PP-1c isoforms were not altered. PP-1c protein levels increased and decreased in nuclear and glycogen-associated fractions, respectively, during EST. Gel filtration determined that a 257 kDa low $K_m$ PP-1$\alpha$ complex decreased during estivation whereas a 76 kDa high $K_m$ complex increased in EST. Western blotting confirmed that the 76 kDa protein consisted of PP-1$\alpha$ and nuclear inhibitor of PP-1 (NIPP-1). A suppression of PP-1 activity factors in the overall metabolic rate depression in estivating snails and the mechanism is mediated through altered cellular localization and interaction with binding partners.

• Journal of Nutrition and Health
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• 제28권10호
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• pp.1022-1030
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• 1995

Saponins are glycosidic compounds present in many plant foods. They are characterized by their ability to lyse cell membranes due to their surface-active properties. Saponins are believed to interact primarily with cholesterol in the cell membrane. In this study, the interaction of soybean(SS) with cell membrane was investigated using erythrocytes as a model. Mechanisms of interaction was also investigated by measuring their binding capacity with different membrane lipid fractions. Throughout the study, gypsophilla saponin(GS) and quillaja saponin(QS) were used to evaluate the membranolytic activity of soybean saponins. All saponins released hemoglobin in a concentration-dependent manner. SS induced 40% hemolysis at the concentration of 400 ppm, however there was no increase in hemoglobin release above 400ppm concentration. 5ppm of GS and 8 ppm of QS hemolyzed 100% of erythrocytes. Isolation of SS fractions by thin layer chromatography revealed that only one non-polar saponin possesses strong hemolytic activity. When saponins were incubated decreased the release of cholesterol. When the hemolytic activity of saponins was measured in the presence of other major membrane lipid components, sphingomyelin significantly reduced the hemolytic activity of SS, while cholesterol reduced the activity of QS. GS showed high affinity to other component(s) in the incubation media as well as lipids. These results suggest that the membranolytic activity of saponins are related to their specific chemical structure, which determines the interaction behavior between saponins and different membrane components, and thereby influence the biological activity.

• BMB Reports
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• 제38권6호
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• pp.717-724
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• 2005

The nontoxic B subunit of cholera toxin (CTB) can significantly increase the ability of proteins to induce immunological tolerance after oral administration, when it was conjugated to various proteins. Recombinant CTB offers great potential for treatment of autoimmune disease. Here we firstly investigated the feasibility of silkworm baculovirus expression vector system for the cost-effective production of CTB under the control of a strong polyhedrin promoter. Higher expression was achieved via introducing the partial non-coding and coding sequences (ATAAAT and ATGCCGAAT) of polyhedrin to the 5' end of the native CTB gene, with the maximal accumulation being approximately 54.4 mg/L of hemolymph. The silkworm bioreactor produced this protein vaccine as the glycoslated pentameric form, which retained the GM1-ganglioside binding affinity and the native antigenicity of CTB. Further studies revealed that mixing with silkworm-derived CTB increases the tolerogenic potential of insulin. In the nonconjugated form, an insulin : CTB ratio of 100 : 1 was optimal for the prominent reduction in pancreatic islet inflammation. The data presented here demonstrate that the silkworm bioreactor is an ideal production and delivery system for an oral protein vaccine designed to develop immunological tolerance against autoimmune diabetes and CTB functions as an effective mucosal adjuvant for oral tolerance induction.

• BMB Reports
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• 제38권6호
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• pp.676-682
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• 2005

To date, no 8-oxoguanine-specific endonuclease-coding gene has been identified in Thermotoga maritima of the order Thermotogales, although its entire genome has been deciphered. However, the hypothetical protein Tm1821 from T. maritima, has a helix-hairpin-helix motif that is considered to be important for DNA binding and catalytic activity. Here, Tm1821 was overexpressed in Escherichia coli and purified using Ni-NTA affinity chromatography, protease digestion, and gel filtration. Tm1821 protein was found to efficiently cleave an oligonucleotide duplex containing 8-oxoguanine, but Tm1821 had little effect on other substrates containing modified bases. Moreover, Tm1821 strongly preferred DNA duplexes containing an 8-oxoguanine:C pair among oligonucleotide duplexes containing 8-oxoguanine paired with four different bases (A, C, G, or T). Furthermore, Tm1821 showed AP lyase activity and Schiff base formation with 8-oxoguanine in the presence of $NaBH_4$, which suggests that it is a bifunctional DNA glycosylase. Tm1821 protein shares unique conserved amino acids and substrate specificity with an 8-oxoguanine DNA glycosylase from the hyperthermophilic archaeon. Thus, the DNA recognition and catalytic mechanisms of Tm1821 protein are likely to be similar to archaeal repair protein, although T. maritima is an eubacterium.